Now that it would become imperative for the world to shift over to the use of clean renewable energies-especially, the solar-for meeting and securing its energy requirements of the future, and also for safeguarding the environment from further deterioration, which has now become hugely damaging to the human as well as all other kinds of life on earth, it would be just in place to narrate as to how and how much, and from where the solar energy is going to be captured for the future energy requirements of the Arab as well as the entire world.

The quantum of energy available to the earth and its atmosphere in the form of solar radiations is about 5.2x10²⁴ Joules per year, which is 165,000 TW in terms of available power. This amount is more than 11,000 times the entire world primary energy consumption in the year 2004.

The focus on solar energy as future replacement to fossil fuels is due to the fact that this is the most important form of renewable energy; with all other forms of renewable energy, barring few, being indirect manifestations of this form. Solar energy is clean, and its availability reliable, everlasting and abundant. The massive damage to the environment by the large-scale use of fossil fuels during the past few decades is compelling to look for cleaner alternatives of energy, and thus the use of solar energy, for the promises it holds, would have to emerge as the main alternative to fossil fuels, sooner than later. Although solar technologies promise satisfying large scale thermal and electric energy needs, some of the direct solar energy technologies of domestic utility, such as, water and space heating, and photovoltaic systems are already well established and growing rapidly.

What follows ahead is mainly the presentation of some relevant facts and figures from the published reports by different agencies, and the calculated figures in respect of utilization of solar energy. A simplified approach, from the point of view of general understanding, has been adopted for carrying out the calculations without considering the more serious aspects of engineering details.

The total primary energy consumption figures for the world for the year 2004 were, on average, 220 million barrels of oil equivalent per day, which, in terms of thermal watts become 14.5 terawatts (1barrel of oil 1600 kWh Thermal). The Arab World countries' share in the above consumption was about 7.6 million barrels of oil equivalent per day, which is about 3.5% of the total. As per projections, the total primary energy requirements of the world by the year 2050, would be 790 million barrels of oil equivalent per day, or, about 52.6 terawatts thermal or 20 terawatts electric (taking the efficiency for thermal to electric conversion to be 38%).

Deserts and desert-like regions-where incidences of solar radiation are very high-are most suitable for capturing the solar energy and converting the same into thermal/electric energy. As per a UNEP estimate, the total deserts or desert-like regions over the earth stretch across 36 million km², which receive direct normal solar radiation of 2.4 TWh/km²/year or 274 MW/km² from the sun.

Of these total deserts on the earth, the deserts in the Arab World form a major part. Incidence of direct normal solar radiation on these desert surfaces ranges from 2.2-2.8 TWh/km²/year, with the average being 2.5 TWh/km²/year. This is well above the threshold value of 2.0 TWh/km²/year for the technical and economical potentials of CSP Technology. Thus, the Arabian deserts, like other desert areas in the world, have huge potential for capturing the solar energy and catering to the various energy needs of the Arab World as well as its neighboring countries, be it thermal or electric.

The electricity consumption figures for the Arab World (twenty countries), as reported in the annual statistical report of OAPEC for the year 2006, suggest a compound growth rate of 5.7% for the period 2000-2005 for all countries of the Arab World combined. If the same rate of growth is maintained, the electricity consumption for these countries is expected to reach 875 TWh by the year 2015, which is 1.75 times the level of consumption of 500 TWh for the year 2005. The largest energy consumers among the Arab World countries are Saudi Arabia, Egypt and UAE, accounting for 30.5%, 17.1% and 10.7% respectively of total consumption for these countries in the year 2005.

To meet the expected electric energy demand of the Arab World countries for 2015, solar fields, measuring about 2350 km² in total area (that is, a square of about 48.5 km a side), would be required to capture the radiation conditions prevalent in these countries, with the combined collector and cycle efficiency of 15%. Each country may set up solar fields of suitable areas in its deserts, in proportion to its respective share in the total demand. Alternatively, about 1440 million barrels of oil equivalent per year or 3.95 million barrels of oil equivalent per day would be required to satisfy this demand.

To meet the total world energy demand of 20TW by the year 2050 from the world deserts, solar fields, measuring a total of 48x10⁴ km² in area, would be required to be set up, creating the combined collector and cycle efficiency of 15%. This area is just 1.33% of the total world deserts area.

The area for the solar fields as above is comparable with 40.4x10⁴ km², obtained by an alternative procedure of calculation, wherein the total solar radiations falling over the entire globe, that is 1.65x10⁵ TW, and the total area of the entire globe, that is about 5x10⁸ km^2, are considered.

The twenty Arab World countries have all practical futuristic possibilities of supplying at least thirty percent of the total world energy demand of 20 TW (electric) by 2050, from their vast solar rich deserts, by erecting solar farms on them to generate power and export the same to neighboring countries. The strategic proximity of the Arab World countries to many European, Asian, African and other countries would be of crucial advantage in this respect.

The Arab World countries may well form an energy league for this purpose, say, the "Arab Solar Energy League (ASEL)", on lines of the petroleum organization OAPEC, for better coordination and control of related activities such as, setting up of solar projects, generation, distribution and transmission of power, agreements with potential buyer countries, pricing, deciding on currency of exchange and other such related matters.

Thirty percent of the total world energy demand by 2050 would be 40 TW in terms of solar radiations, considering an overall efficiency of 15%. If solar fields are erected for capturing these many radiations equally over the deserts of each of the 20 Arab World countries, the area of each such fields, for the average radiation conditions of 2.5 TWh/km²/yr, would be 7008 km², that is, a square of 83.7 km a side.

The cumulative area of all the 20 fields would be 20x7008 (km²) = 14.0x10⁴ km^2, which is about 1.1% of the total Arab World land area. 237 million barrels of oil equivalent would be required per day if the 30% of the world energy demand were to come from oil.

It will be appropriate to note here that a moderate figure of 15% has been taken throughout for the combined collector and cycle efficiency for solar area calculations. This figure for the overall efficiency is absolutely realistic in view of the technological developments that are continually being made for improving the collector efficiency. Literature cites efficiency values of more than 20% as the optimum for CSP plants with suitable concentration ratios and power cycles.
The areas calculated for the solar fields are the net as required for collecting the radiations alone, and do not include additional areas that may be essential for other installations.